Antimicrobial composition

ABSTRACT

A method for antimicrobial treatment comprising applying to microbes a composition containing a diluting solvent (e.g., water), an antimicrobially-active solvent having a density different from the density of the diluting solvent, and an optional cosolvent, surfactant, or additional antimicrobial agent, wherein the amount of antimicrobially-active solvent or additional antimicrobial agent is sufficiently high and the amount of cosolvent or surfactant is sufficiently low so that the composition will provide greater than a 1-log order reduction in the population of bacteria or spores of  Bacillus cereus  within 10 seconds at 60° C. Preferred methods of the invention employ compositions containing an additional antimicrobial agent such as peroxyacetic acid. Compositions for use in the method can be prepared as concentrates, and used full strength or in diluted form.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation-in-part of application Ser.No. 09/560,170, filed Apr. 28, 2000, and a continuation-in-part ofapplication Ser. No. 09/641,775, filed Aug. 18, 2000.

TECHNICAL FIELD

[0002] This invention relates to compositions that can be used, forexample, to clean, reduce the microbial population of, or sterilizesurfaces, and to compositions that can be used for aseptic packaging.

BACKGROUND

[0003] There has been a longstanding need for antimicrobial agentshaving improved antimicrobial efficacy and improved speed of action. Thespecific requirements for such agents vary according to the intendedapplication (e.g., sanitizer, disinfectant, sterilant, aseptic packagingtreatment, etc.) and the applicable public health requirements. Forexample, as set out in Germicidal and Detergent Sanitizing Action ofDisinfectants, Official Methods of Analysis of the Association ofOfficial Analytical Chemists, paragraph 960.09 and applicable sections,15th Edition, 1990 (EPA Guideline 91-2), a sanitizer should provide a99.999% reduction (5-log order reduction) within 30 seconds at roomtemperature, 25±2° C., against several test organisms.

[0004] Many antimicrobial agents (e.g., iodophors, peracids,hypochlorites, chlorine dioxide, ozone, etc.) have a broad spectrum ofantimicrobial properties. However, these agents sometimes haveinadequate activity against bacterial spores, fungal spores, and fungi.Killing, inactivating, or otherwise reducing the active population ofbacterial spores and fungi on surfaces is particularly difficult.Bacterial spores have a unique chemical composition of spore layers thatmake them more resistant than vegetative bacteria to the antimicrobialeffects of chemical and physical agents. Likewise, the unique chemicalcomposition of fungal cells, especially mold spores, makes them moreresistant to chemical and physical agents than are other microorganisms.This resistance can be particularly troublesome when the spores or fungiare located on surfaces such as food, food contact sites, ware,hospitals and veterinary facilities, surgical implements, and hospitaland surgical linens and garments.

[0005] Control of the mold Chaetomium funicola, and of bacterialspore-forming microorganisms of the Bacillus species, can be especiallyimportant during food packaging, particularly during cold or hot asepticfilling of food and beverage products. Microorganisms of the Bacillusspecies include Bacillus cereus, Bacillus mycoides, Bacillus subtilis,Bacillus anthracis, and Bacillus thuringiensis. These lattermicroorganisms share many phenotypical properties, have a high level ofchromosomal sequence similarity, and are known enterotoxin producers.Bacillus cereus is one of the most problematic because Bacillus cereushas been identified as possessing increased resistance to germicidalchemicals used to decontaminate environmental surfaces. For example,Blakistone et al., Efficacy of Oxonia Active Against SelectedSporeformers, Journal of Food Protection, Volume 62, pp.262-267,reported that Bacillus cereus was more tolerant to the effects ofconventionally formulated peroxyacetic acid germicides than all otherspore-forming bacteria tested, including other Bacillus and Clostridiumspecies.

[0006]Bacillus cereus is frequently diagnosed as a cause ofgastrointestinal disorders and has been suggested to be the cause ofseveral food-borne illness outbreaks. Due to its rapid sporulatingcapacity, Bacillus cereus easily survives in the environment. Bacilluscereus is omnipresent in nature, and consequently can usually be foundin animal feed and fodder. Bacillus cereus can contaminate raw milk viafeces and soil, and can survive intestinal passage in cows and thepasteurization process.

[0007]Bacillus cereus is also known to cause serious human illness viaenvironmental contamination. For example, Bacillus cereus is known tocause post-traumatic injury eye infections, which can result in visualimpairment or loss of vision within 12-48 hours after infection. Inaddition, Bacillus cereus is regarded as transferable from washedsurgical garments to patients.

[0008] Agents having greater or faster activity against bacterialspores, fungi, and other resistant microorganisms (particularlymicroorganisms of the Bacillus species) could help meet a substantialpublic health need, and one that is not adequately addressed by currentcommonly-used antimicrobial agents.

SUMMARY OF THE INVENTION

[0009] The present invention provides, in one aspect, a method forantimicrobial treatment comprising applying to microbes a compositioncontaining a diluting solvent (e.g., water), an antimicrobially-activesolvent having a density different from the density of the dilutingsolvent, and an optional cosolvent, surfactant, or additionalantimicrobial agent, wherein the amount of antimicrobially-activesolvent or additional antimicrobial agent is sufficiently high and theamount of cosolvent or surfactant is sufficiently low so that thecomposition will provide greater than a 1-log order reduction in thepopulation of bacteria or spores of Bacillus cereus within 10 seconds at60° C. In a preferred aspect, the methods of the invention providebroader spectrum antimicrobial action, providing greater than a 1-logorder reduction within 10 seconds at 60° C. in one or more additionalorganisms such as the mold Chaetomium funicola. In a more preferredaspect, the methods of the invention provide greater than a 1-log orderreduction within 10 seconds at 60° C. in Chaetomium funicola, Bacillussubtilis and Bacillus cereus.

[0010] In another aspect, the invention provides a method forantimicrobial treatment, comprising applying to microbes a compositionas described above, wherein the composition further comprises suchadditional antimicrobial agent. In a particularly preferred embodiment,the additional antimicrobial agent comprises a peracid such asperoxyacetic acid; a peroxide such as hydrogen peroxide; or a halogencontaining compound such as hypochlorous acid (or its salts), chlorinedioxide, hypobromous acid (or its salts), or an interhalide such asiodine monochloride, iodine dichloride, iodine tetrachloride, brominechloride, iodine monobromide, or iodine dibromide.

[0011] In yet another aspect, the invention provides an antimicrobialconcentrate and instructions for mixing the concentrate with water,wherein the concentrate comprises an antimicrobially-active solvent thathas a density different from that of water, an optional cosolvent orsurfactant, and an optional additional antimicrobial agent, the amountsof antimicrobially-active solvent and optional additional antimicrobialagent being. sufficiently high and the amount of cosolvent or surfactantbeing sufficiently low so that the composition will provide greater thana 1-log order reduction in the population of bacteria or spores ofBacillus cereus within 10 seconds at 60° C. In a particularly preferredembodiment, the composition comprises said additional antimicrobialagent and the amount of antimicrobially-active solvent is sufficientlyhigh and the amount of cosolvent or surfactant is sufficiently low sothat the composition does not form a clear single-phase solution ormicroemulsion when the concentrate is mixed with water according to theinstructions.

[0012] In a further aspect, the invention provides an antimicrobialcomposition comprising a diluting solvent, an antimicrobially-activesolvent having a density that is different from the density of thediluting solvent, an additional antimicrobial agent, and an optionalcosolvent or surfactant, the amounts of antimicrobially-active solventand of additional antimicrobial agent being sufficiently high and theamount of cosolvent or surfactant being sufficiently low so that thecomposition will provide greater than a 1-log order reduction in thepopulation of bacteria or spores of Bacillus cereus or the moldChaetomium funicola within 10 seconds at 60° C.

[0013] In yet another aspect, the invention provides an antimicrobialconcentrate and instructions for mixing the concentrate with water,wherein the concentrate comprises an antimicrobially-active solvent thathas a density different from that of water, an optional cosolvent orsurfactant, and an additional antimicrobial agent, the amounts ofantimicrobially-active solvent and additional antimicrobial agent beingsufficiently high so that the composition will provide greater than a1-log order reduction in the population of bacteria or spores ofBacillus cereus or the mold Chaetomium funicola within 10 seconds at 60°C. In a particularly preferred embodiment, the composition comprises asufficiently high amount of additional antimicrobial agent andantimicrobially-active solvent such that the composition forms a clearsingle-phase solution when the concentrate is mixed with water accordingto the instructions, and provides greater than a 1-log order reductionin the population of bacteria or spores of Bacillus cereus or Bacillussubtilis and in the population of the mold Chaetomium funicola within 10seconds at 60° C.

[0014] The method and compositions of the invention are especiallyuseful for aseptic packaging, re-use clean-in-place (CIP) orclean-out-of-place (COP) systems, hospital disinfectants, veterinaryclinic disinfectants, and as sporicides or sterilants.

DETAILED DESCRIPTION

[0015] As used in this invention, the term “sterilant” refers to aphysical or chemical agent or process capable of destroying all forms oflife (including bacteria, viruses, fungi, and spores) on inanimatesurfaces. One procedure is described in A.O.A.C. Sporicidal Activity ofDisinfectants, Official Methods of Analysis of the Association ofOfficial Analytical Chemists, paragraph 966.04 and applicable sections,15^(th) Edition, 1990 (EPA Guideline 91-2) As used in this invention,the term “antimicrobial composition” refers to a composition having theability to cause greater than a 90% reduction (1-log order reduction) inthe population of bacteria or spores of Bacillus species within 10seconds at 60° C., using the above-mentioned Germicidal and DetergentSanitizing Action of Disinfectants procedure. Preferably, Bacilluscereus or Bacillus subtilis are used in such procedure. Also preferably,the antimicrobial compositions of the invention provide greater than a99% reduction (2-log order reduction), more preferably greater than a99.99% reduction (4-log order reduction), and most preferably greaterthan a 99.999% reduction (5-log order reduction) in such populationwithin 10 seconds at 60° C. Preferably, the antimicrobial compositionsof the invention also provide greater than a 99% reduction (2-log orderreduction), more preferably greater than a 99.99% reduction (4-log orderreduction), and most preferably greater than a 99.999% reduction (5-logorder reduction) in the population of one or more additional organismssuch as the mold Chaetomium funicola. Because in their broadest sensethese definitions for antimicrobial activity are different from some ofthe current governmental regulations, the use in connection with thisinvention of the term “antimicrobial” is not intended to indicatecompliance with any particular governmental standard for antimicrobialactivity.

[0016] As used in this invention, the term “sporicide” refers to aphysical or chemical agent or process having the ability to causegreater than a 90% reduction (1-log order reduction) in the populationof spores of Bacillus cereus or Bacillus subtilis within 10 seconds at60° C. Preferably, the sporicidal compositions of the invention providegreater than a 99% reduction (2-log order reduction), more preferablygreater than a 99.99% reduction (4-log order reduction), and mostpreferably greater than a 99.999% reduction (5-log order reduction) insuch population within 10 seconds at 60° C.

[0017] As used in this invention, the term “sanitizer” refers to anagent that reduces the number of bacterial contaminants to safe levelsas judged by public health requirements. Preferably, sanitizers for usein this invention will provide at least a 99.999% reduction (5-log orderreduction) using the Germicidal and Detergent Sanitizing Action ofDisinfectants procedure referred to above.

[0018] As used in this invention, the term “disinfectant” refers to anagent that kills all vegetative cells including most recognizedpathogenic microorganisms, using the procedure described in A.O.A.C. UseDilution Methods, Official Methods of Analysis of the Association ofOfficial Analytical Chemists, paragraph 955.14 and applicable sections,15th Edition, 1990 (EPA Guideline 91-2).

[0019] As used in this invention, the term “preservative” refers to anagent that extends the storage life of food and non-food products byretarding or preventing deterioration of flavor, odor, color, texture,appearance, nutritive value, or safety. A preservative need not providea lethal, irreversible action resulting in partial or complete microbialcell destruction or incapacitation. Sterilants, sanitizers,disinfectants, sporicides, viracides and tuberculocidal agents providesuch an irreversible mode of action, sometimes referred to as“bactericidal” action. In contrast, a preservative can provide aninhibitory or bacteriostatic action that is reversible, in that thetarget microbes can resume multiplication if the preservative isremoved. The principal differences between a preservative and asanitizer primarily involve mode of action (a preservative preventsgrowth rather than killing microorganisms) and exposure time (apreservative has days to months to act whereas a sanitizer has at most afew minutes to act).

[0020] When applied to microbes (e.g., when applied to a surfacecontaining microbes), the compositions of the invention exhibitantimicrobial action. The mechanism by which such action takes place isnot completely understood. However, as shown in the Examples set outbelow, very rapid and substantially complete antimicrobial action can beattained.

[0021] Some preferred compositions and methods of the invention provide“pseudo-stabel” antimicrobial compositions that phase-separate followingapplication of the composition to a surface. These compositions can alsobe described as exhibiting “phase-splitting” characteristics. The term“phase” refers to a homogeneous fluid portion that is present in or thatcan form in a fluid system. The term “phases” refers to the presence ofmore than one phase in a heterogeneous fluid system. The term“pseudo-stable” refers to a composition that forms a single phase whensubjected to mild mixing or other agitation and retains that singlephase for a sufficient period of time so that the composition can beapplied to a surface, but which will promptly form two or more phaseswhen left undisturbed. The term “phase-splitting” is meant to describe asingle phase antimicrobially-active solvent-containing composition thatforms at least two laminar phases promptly after being applied atop agenerally horizontal surface or on a generally vertical surface, wherebya film containing a concentrated amount of the antimicrobially-activesolvent lies between the surface and a film containing a much loweramount of the antimicrobially-active solvent. In a composition that hasundergone phase splitting, the phase containing a concentrated amount ofthe antimicrobially-active solvent will be referred to as the solventphase, and the phase containing a much lower amount of theantimicrobially-active solvent will be referred to as the dilute phaseor diluting phase. For example, on counters, floors and other generallyhorizontal surfaces, the solvent phase will lie atop the surface (oratop microbes on the surface) and under the dilute phase or phases. Onwalls or other generally vertical surfaces, the solvent phase will lieadjacent the surface (or adjacent microbes on the surface) and under thedilute phase or phases. In such compositions, as is described in moredetail below, attainment of pseudo-stable phase-splitting behavior canbe achieved by employing a sufficiently high amount ofantimicrobially-active solvent and a sufficiently low amount ofcosolvent or surfactant.

[0022] In some compositions of the invention (and in some methods of theinvention employing such compositions), the amount ofantimicrobially-active solvent is sufficiently high and the amount ofcosolvent or surfactant is sufficiently low so that the compositionforms a “quasi-stable” antimicrobial composition. Such compositions havea clear or slightly cloudy appearance, do not form a clear single-phasesolution or microemulsion, and do not undergo phase-splitting. However,they are antimicrobial compositions as defined herein. If in suchquasi-stable compositions the amount of antimicrobially-active solventis increased sufficiently, or if the amount of cosolvent or surfactantis decreased sufficiently, then these compositions will becomepseudo-stable. Thus, these quasi-stable compositions almost exhibitpseudo-stable behavior, and will do so if modified as taught herein. Asshown in some of the Examples set out below, these quasi-stablecompositions can provide significant antimicrobial activity even thoughthey do not undergo phase-splitting during use.

[0023] For simplicity, the remainder of this specification will discusscompositions that upon standing will form clear one-phase mixtures,cloudy two-phase dispersions or phase-splitting two-phase mixtures, itbeing understood that compositions forming three or more phases uponstanding could be employed if desired.

[0024] The compositions of the invention can be formulated and sold foruse as is, or as solvent concentrates. If desired, such concentrates canbe used full-strength as antimicrobial agents. However, the concentratestypically will be diluted with a fluid (e.g., water) that subsequentlyforms the dilute phase. Preferably, the concentrate forms a single phasebefore such dilution and remains so while stored in the container inwhich it will be sold. When combined with water or other desireddiluting fluid at an appropriate dilution level and subjected to mildagitation (e.g., by stirring or pumping the composition), somecompositions of the invention will form a pseudo-stable dispersion, andother compositions of the invention will form a clear or quasi-stablesolution or dispersion. If a pseudo-stable composition is formed, thenthe composition preferably remains in the pseudo-stable state for asufficiently long period so that the composition can be applied to asurface before the onset of phase separation. The pseudo-stable stateneed only last for a few seconds when suitably rapid applicationtechniques such as spraying are employed, or when agitation duringapplication is employed. The pseudo-stable state desirably lasts for atleast one minute or more after mixing and while the composition isstored in a suitable vessel, and preferably lasts for five minutes ormore after mixing. Often normal refilling or replenishment of theapplicator (e.g., by dipping the applicator in the composition) willprovide sufficient agitation to preserve the pseudo-stable state of thecomposition during application.

[0025] Some of the highest observed levels of antimicrobial activityhave been observed using pseudo-stable antimicrobial compositions of heinvention. However, very high levels have also been observed for someclear or quasi-stable antimicrobial compositions of the invention. Forsome applications these clear or quasi-stable antimicrobial compositionssolutions or dispersions will be preferred, as they require little or nomixing before or during use, and have a reduced tendency to separateduring storage.

[0026] A variety of fluids can be used as the diluting solvent,including water in its liquid form; steam; condensed gases and othersupercritical fluids (e.g., CO₂); perchloroethylene; oils such assilicone oils (e.g., siloxanes), gear oils, transaxle oils, mineral oilsor vegetable oils; and carboxylic esters such as methyl soyate. Mixturesof diluting solvents can be used if desired. Especially useful oilsinclude food grade or food-derived oils, flavorings, or fragrance oils.Preferably, the diluting solvent consists essentially of or consists ofwater in its liquid form. The remainder of this specification willprimarily discuss the use of water in its liquid form as the dilutingsolvent, it being understood that other suitable fluids could be addedto or substituted for water in its liquid form if desired.

[0027] The compositions of the invention can contain a variety ofantimicrobially-active solvents. The antimicrobially-active solventpreferably is insoluble, or only sparingly soluble, in the dilutingsolvent. Thus for compositions containing water as the diluting solvent,and for concentrates intended to be diluted with water, theantimicrobially-active solvent preferably will have a water solubilityless than about 5 wt. %, more preferably less than about 3 wt. %, andmost preferably less than about 2 wt. %.

[0028] In general, the antimicrobially-active solvent is selected basedupon the characteristics of the surface and microbes to which theantimicrobial composition will be applied and upon the nature of anycoating, soil or other material that will be contacted by theantimicrobial composition and optionally removed from the surface. Polarsolvents, and solvents that are capable of hydrogen bonding typicallywill perform well on a variety of surfaces and microbes and thus arepreferred. Preferably, the antimicrobially-active solvent also has ahigh flashpoint (e.g., greater than about 30° C., more preferablygreater than about 50° C., and most preferably greater than about 100°C.), low odor and low human and animal toxicity. Most preferably theantimicrobially-active solvent is a food-grade or cosmetic or flavorantadditive.

[0029] Preferred antimicrobially-active solvents having a densitydifferent from that of water (and thus especially useful in compositionsthat will be diluted with water and applied atop horizontal or generallyhorizontal surfaces) include acetamidophenol (specific gravity 1.027);acetanilide (specific gravity 1.219; water solubility<1%); acetophenone(specific gravity 1.0238; water solubility<1%);[2-acetyl-1-methylpyrrole (specific gravity 1.04); benzyl acetate(specific gravity 1.0515; water solubility<1%); benzyl alcohol (specificgravity 1.0413; water solubility˜4%); benzyl benzoate (specific gravity1.118; water solubility<1%); benzyloxyethanol (specific gravity 1.07;water solubility<1%); ethers or hydroxyethers such as ethylene glycolphenyl ether (specific gravity 1.104; water solubility 2.3%;commercially available as DOWANOL EPH™ from Dow Chemical Co.) andpropylene glycol phenyl ether (specific gravity 1.063; water solubility1.1%; commercially available as DOWANOL PPH™ from Dow Chemical Co.);essential oils (e.g., benzaldehyde, pinenes (alphas, betas, etc.),terpineols, terpinenes, carvone, cinnamealdehyde, borneol and itsesters, citrals, ionenes, jasmine oil, limonene, dipentene, linalool andits esters); dibasic esters such as dimethyl adipate, dimethylsuccinate, dimethyl glutarate (often available in a mix with specificgravities greater than 1.00; including products available under thetrade designations DBE, DBE-3, DBE-4, DBE-5, DBE-6, DBE-9, DBE-IB, andDBE-ME from DuPont Nylon), dimethyl malonate, diethyl adipate, diethylsuccinate, diethyl glutarate, dibutyl succinate, and dibutyl glutarate;dialkyl carbonates such as dimethyl carbonate, diethyl carbonate,dipropyl carbonate, diisopropyl carbonate, and dibutyl carbonate; C₁₋₁₆protonated carboxylic acids such as 2-ethyl-1-hexanoic acid, butyricacid, octanoic acid, heptanoic acid, nonanoic acid, and decanoic acid;C₁₋₁₂ organic anhydrides such as acetic anhydride, succinic anhydride,phthalic anhydride, maleic anhydride, and alkyl or alkenyl succinicanhydrides; organo-nitriles such as acetonitrile and benzonitrile;organo-phosphates and phosphonates such as tributyl phosphate, tripropylphosphate, 2-ethyl-1-hexyl phosphate; and phthalate esters such asdibutyl phthalate, diethylhexyl phthalate, and diethyl phthalate. Thewater solubilities noted above are room temperature values. Benzylalcohol, phenylethanol, essential oils, dibasic esters, dialkylcarbonates, ethylene glycol phenyl ether and propylene glycol phenylether are particularly preferred antimicrobially-active solvents.Mixtures of antimicrobially-active solvents can be used if desired.

[0030] The compositions of the invention should contain sufficientantimicrobially-active solvent to provide the desired rate and type ofmicrobial reduction. Usually, antimicrobial concentrates of theinvention will contain at least about 5 wt. % antimicrobially-activesolvent, preferably at least about 25 wt. % antimicrobially-activesolvent, more preferably at least about 65 wt. % antimicrobially-activesolvent, and most preferably about 75 to about 95 wt. %antimicrobially-active solvent.

[0031] The compositions of the invention can contain one or morecosolvents or surfactants to assist in providing pseudo-stable orquasi-stable behavior. In general, cosolvents or surfactants that arepresent at concentrations below those at which single-phase couplingarises, or cosolvents or surfactants that are relatively inefficient orineffective (with respect to their ability completely to solubilize ordisperse the antimicrobially-active solvent in the diluting solvent andform a single-phase system), are preferred over cosolvents orsurfactants that are present at higher concentrations or are moreefficient or effective. This differs from the approach normally takenwhen formulating compositions containing cosolvents or surfactants.Normally, cosolvents and surfactants are selected for their ability topromote formation of stable single-phase solutions, microemulsions, ordispersions.

[0032] A variety of cosolvents can be employed. In general, thecosolvent is selected based upon the characteristics of the chosenantimicrobially-active solvent and the solubility of the chosenantimicrobially-active solvent in the diluting solvent. For compositionsin which water serves as the diluting solvent, the cosolvent generallywill have higher water solubility than the water solubility of thechosen solvent. Preferably, the cosolvent has a high flashpoint (e.g.,greater than about 30° C., more preferably greater than about 50° C.,and most preferably greater than about 100° C.), low odor and low humanand animal toxicity.

[0033] Preferred cosolvents include 2-(2-aminoethoxy)ethanol,monoethanolamine, diethanolamine, triethanolamine, amyl acetate, amylalcohol, butanol, 3-butoxyethyl-2-propanol, butyl acetate, n-butylpropionate, cyclohexanone, diacetone alcohol, diethoxyethanol,diethylene glycol methyl ether, diethylene glycol n-butyl ether,diisobutyl carbinol, diisobutyl ketone, dimethyl heptanol, dipropyleneglycol n-butyl ether, dipropylene glycol methyl ether, dipropyleneglycol propyl ether, dipropylene glycol tert-butyl ether, ethanol, ethylacetate, 2-ethylhexanol, ethyl propionate, ethylene glycol butyl ether,ethylene glycol methyl ether acetate, hexanol, isobutanol, isobutylacetate, isobutyl heptyl ketone, isophorone, isopropanol, isopropylacetate, methanol, methyl amyl alcohol, methyl n-amyl ketone,2-methyl-1-butanol, methyl ethyl ketone, methyl isobutyl ketone,1-pentanol, n-pentyl propionate, 1-propanol, n-propyl acetate, n-propylpropionate, propylene glycol n-butyl ether, propylene glycol ethylether, propylene glycol methyl ether, propylene glycol n-propyl ether,tripropylene glycol methyl ether and tripropylene glycol n-butyl ether.Ethylene glycol butyl ether and dipropylene glycol n-butyl ether areparticularly preferred cosolvents. Mixtures of cosolvents can be used ifdesired.

[0034] Commercially available cosolvents (all of which are availablefrom Union Carbide Corp.) include Butoxyethyl PROPASOL™, Butyl CARBITOL™acetate, Butyl CARBITOL™, Butyl CELLOSOLVE™ acetate, Butyl CELLOSOLVE™,Butyl DIPROPASOL™, Butyl PROPASOL™, CARBITOL™ PM-600, CARBITOL™ LowGravity, CELLOSOLVE™ acetate, CELLOSOLVE™, Ester EEP™, FILMER IBT™,Hexyl CARBITOL™, Hexyl CELLOSOLVE™, Methyl CARBITOL™, Methyl CELLOSOLVE™acetate, Methyl CELLOSOLVE™, Methyl DIPROPASOL™, Methyl PROPASOL™acetate, Methyl PROPASOL™, Propyl CARBITOL™, Propyl CELLOSOLVE™, PropylDIPROPASOL™ and Propyl PROPASOL™.

[0035] The compositions of the invention preferably should not containexcessive cosolvent, as the use of an excess of cosolvent will tend tocause formation of an antimicrobially inert single-phase solution ormicroemulsion. Instead, the amount of cosolvent preferably is justsufficient to provide the desired level of antimicrobial activity.Larger amounts of cosolvent may diminish the antimicrobial effectivenessof the compositions of the invention. Usually, antimicrobialconcentrates of the invention will contain 0 to about 50 wt. %cosolvent, more preferably 0 to about 25 wt. % cosolvent, and mostpreferably 0 to about 20 wt. % cosolvent.

[0036] A variety of surfactants can be employed. In general, thesurfactant identity and use level is selected based upon thecharacteristics of the chosen antimicrobially-active solvent and thesolubility of the chosen antimicrobially-active solvent in the dilutingsolvent. For compositions in which water serves as the diluting solvent,the surfactant preferably will have an HLB value greater than or equalto about 13, or less than or equal to about 6. This value reflects theabove-noted preference in the present invention for employingsurfactants that are relatively inefficient or ineffective asemulsifiers. Preferably, the surfactant does not tend to cause formationof insoluble deposits, and has low odor and low toxicity. Mixtures ofsurfactants can be used if desired.

[0037] Preferred anionic surfactants include C₆-C₂₄ alkylbenzenesulfonates; C₆-C₂₄ olefin sulfonates; C₆-C₂₄ paraffin sulfonates; cumenesulfonate; xylene sulfonate; C₆-C₂₄ alkyl naphthalene sulfonates; C₆-C₂₄alkyl or dialkyl diphenyl ether sulfonates or disulfonates, C₄-C₂₄ monoor dialkyl sulfosuccinates; sulfonated or sulfated fatty acids; C₆-C₂₄alcohol sulfates (preferably C₆-C₁₂ alcohol sulfates); C₆-C₂₄ alcoholether sulfates having 1 to about 20 ethylene oxide groups; and C₄-C₂₄alkyl, aryl or alkaryl phosphate esters or their alkoxylated analogueshaving 1 to about 40 ethylene, propylene or butylene oxide units ormixtures thereof.

[0038] Preferred nonionic surfactants include C₆-C₂₄ alcohol ethoxylates(preferably C₆-C₁₄ alcohol ethoxylates) having 1 to about 20 ethyleneoxide groups (preferably about 9 to about 20 ethylene oxide groups);C₆-C₂₄ alkylphenol ethoxylates (preferably C₈-C₁₀ alkylphenolethoxylates) having 1 to about 100 ethylene oxide groups (preferablyabout 12 to about 20 ethylene oxide groups); C₆-C₂₄ alkylpolyglycosides(preferably C₆-C₂₀ alkylpolyglycosides) having 1 to about 20 glycosidegroups (preferably about 9 to about 20 glycoside groups); C₆-C₂₄ fattyacid ester ethoxylates, propoxylates or glycerides; and C4-C₂₄ mono ordi alkanolamides .

[0039] Preferred cationic surfactants include quaternary amine compoundshaving the formula:

[0040] where R, R′, R″ and R′″ are each a C₁-C₂₄ alkyl, aryl or aralkylgroup that can optionally contain one or more P, O, S or N heteroatoms,and X is F, Cl, Br, I or an alkyl sulfate.

[0041] Preferred amphoteric surfactants include amine oxide compoundshaving the formula:

[0042] where R, R′, R″ and R′″ are each a C₁-C₂₄ alkyl, aryl or aralkylgroup that can optionally contain one or more P, O, S or N heteroatoms.

[0043] Another class of preferred amphoteric surfactants includesbetaine compounds having the formula:

[0044] where R, R′, R″ and R′″ are each a C₁-C₂₄ alkyl, aryl or aralkylgroup that can optionally contain one or more P, O, S or N heteroatoms,and n is about 1 to about 10.

[0045] The antimicrobial compositions of the invention should notcontain excessive amounts of surfactant, lest an antimicrobiallyinactive single-phase solution or microemulsion be formed. Instead, theamount of surfactant should be just sufficient to provide the desiredlevel of antimicrobial activity. Larger amounts of surfactant maydiminish the antimicrobial effectiveness of the compositions of theinvention. Usually, the solvent concentrates of the invention willcontain no more than about 10 wt. % surfactant, more preferably 0 toabout 3 wt. % surfactant and most preferably 0 to about 1 wt. %surfactant. Most preferably, the concentrates are substantiallysurfactant-free.

[0046] The antimicrobial compositions of the invention preferablycontain an additional antimicrobial agent. This additional antimicrobialagent can be dissolved or dispersed in the antimicrobially-activesolvent or in the diluting solvent. Desirably, the additionalantimicrobial agent will preferentially dissolve or disperse in theantimicrobially-active solvent rather than in the diluting solvent.Suitable additional antimicrobial agents include carboxylic acids,diacids, or triacids (e.g., butyric acid, heptanoic acid, octanoic acid,nonanoic acid, decanoic acid, salycic acid, mandelic acid, succinicacid, adipic acid, glutaric acid, EDTA and citric acid), carboxylicesters (e.g., p-hydroxy alkyl benzoates and alkyl cinnamates), sulfonicacids (e.g., dodecylbenzene sulfonic acid), iodo-compounds or activehalogen compounds (e.g., iodine, interhalides, polyhalides, metalhypochlorites, hypochlorous acid, metal hypbromites, hypobromous acid,chloro- and bromo-hydantoins, chlorine dioxide and sodium chlorite),active oxygen compounds including hydrogen peroxide, isolated orequilibrium derived or isolated peracids such as chloroperbenzoic acids,peracetic acid, perheptanoic acid, peroctanoic acid, perdecanoic acid,performic acid, percitric acid, perglycolic acid, perlactic acid,perbenzoic acid, and monoester peracids derived from diacids or diesters(e.g., such as adipic, succinic, glutaric, or malonic acid and mixturesthereof), organic peroxides including benzoyl peroxide, alkyl benzoylperoxides, ozone, singlet oxygen generators, and mixtures thereof,phenolic derivatives (e.g., o-phenyl phenol, o-benzyl-p-chlorophenol,tert-amyl phenol and C₁-C₆ alkyl hydroxy benzoates), quaternary ammoniumcompounds (e.g., alkyldimethylbenzyl ammonium chloride, dialkyldimethylammonium chloride and mixtures thereof), and mixtures of suchantimicrobial agents, in an amount sufficient to provide the desireddegree of microbial protection. Most of the aforementioned additionalantimicrobial agents having about 1-6 carbons, or an ionic charge, wouldbe mostly soluble in the diluting solvent; those with higher carbonnumbers would generally be more soluble in the antimicrobially-activesolvent. In either case, for a pseudo-stable antimicrobial compositionit is preferred to use additional antimicrobial agents that can be drawninto the solvent phase or onto surfaces during phase separation.

[0047] Compositions of the invention containing such optional additionalantimicrobial agents appear to have substantially greater antimicrobialeffectiveness than comparison aqueous solutions or dispersionscontaining the additional antimicrobial agent alone. If present in theantimicrobial concentrates of the invention, the additionalantimicrobial agent preferably is about 0.01 to about 30 wt. % of theconcentrate, more preferably about 0.05 to about 10 wt. % and mostpreferably about 0.1 to about 5 wt. %.

[0048] If desired, the antimicrobial compositions of the invention cancontain various adjuvants such as chelants, builders, thickeners,fragrances, dyes, pH adjusters, anticorrosion additives, antirustadditives and indicators. The types and amounts of such adjuvants willbe apparent to those skilled in the art.

[0049] The compositions of the invention can be formulated to includethe diluting solvent (e.g., water) as sold, or the diluting solvent canbe added at any time up to the time of use. Preferably, the concentratesof the invention contain little or no diluting solvent as sold. Avariety of dilution ratios can be employed, so long as the dilutedcomposition exhibits the desired antimicrobial behavior when applied tothe target microbes. The ingredients in the concentrate can representabout 1 to about 99 wt. % of the diluted mixture, more preferably about5 to about 50 wt. %, and most preferably about 6 to about 25 wt. %. Thediluted antimicrobial compositions preferably contain about 0.01 toabout 50 wt. % of the antimicrobially-active solvent, withconcentrations of about 0.1 to 10 wt. % being more preferred andconcentrations of about 0.5 to about 5 wt. % being most preferred. As afurther guide, the diluted composition preferably containsantimicrobially-active solvent in an amount near the solubility limit ofthe antimicrobially-active solvent in the diluting solvent. In addition,the diluted antimicrobial compositions preferably are aqueous, containadditional antimicrobial agent, and are clear or quasi-stable.

[0050] The compositions of the invention can be sold in the form of akit containing the composition together with suitable directions forcarrying out the method of the invention. Such directions typically willinclude recommended dilution ratios, applications, applicationtechniques and safety warnings.

[0051] Although no longer commercially available, an aqueous floorstripping agent concentrate previously sold in Canada as Fuller Formula3100™ Super Concentrate (Fuller Brush, Québec) could be used as anantimicrobial composition of the invention. However, to do so theconcentrate should be diluted at a ratio not recommended in the productinstructions. Fuller Formula 3100™ Super Concentrate is believed to havecontained about 49 wt. % benzyl alcohol, 17 wt. % monoethanolarnine, 10wt. % sodium decyldiphenyl ether disulfonate and 24 wt. % water.Dilution of the concentrate at a 1:20 concentrate:water ratio wasrecommended on the product instructions. At that dilution ratio, theresulting mixture formed a stable single-phase solution. However, ifdiluted at a sufficiently larger concentrate:water ratio, the resultingmixture forms a quasi-stable or pseudo-stable composition. For example,at a 1:10 concentrate:water ratio, the composition is pseudo-stable andwill undergo phase splitting when applied to a substrate and allowed tostand for a few minutes.

[0052] The antimicrobial compositions of the invention can be used for avariety of domestic or industrial applications, e.g., to reducemicrobial or viral populations on a surface or object or in a body orstream of water. The compositions can be applied in a variety of areasincluding kitchens, bathrooms, factories, hospitals, dental offices andfood plants, and can be applied to a variety of hard or soft surfaceshaving smooth, irregular or porous topography. Suitable hard surfacesinclude, for example, architectural surfaces (e.g., floors, walls,windows, sinks, tables, counters and signs); eating utensils;hard-surface medical or surgical instruments and devices; andhard-surface packaging. Such hard surfaces can be made from a variety ofmaterials comprising, for example, ceramic, metal, glass, wood or hardplastic. Suitable soft surfaces include, for example paper; filtermedia, hospital and surgical linens and garments; soft-surface medicalor surgical instruments and devices; and soft-surface packaging. Suchsoft surfaces can be made from a variety of materials comprising, forexample, paper, fiber, woven or nonwoven fabric, soft plastics andelastomers. The compositions of the invention can also be applied tosoft surfaces such as food and skin. The compositions are also suitablefor application to growing or harvested plant material including leaves,stems, tubers, roots, seeds, and the like.

[0053] The antimicrobial compositions of the invention can be includedin products such as sterilants, sanitizers, disinfectants,preservatives, deodorizers, antiseptics, fungicides, germicides,sporicides, virucides, detergents, bleaches, hard surface cleaners, handsoaps and pre- or post-surgical scrubs. The compositions have particularutility as cold or hot aseptic packaging treatments. The antimicrobialcompositions can also be used in veterinary products such as mammalianskin treatments or in products for sanitizing or disinfecting animalenclosures, pens, watering stations, and veterinary treatment areas suchas inspection tables and operation rooms.

[0054] The antimicrobial compositions of the invention can be used fortreating skin diseases on animals (especially mammals), or those whichspread via transfer to air or surface substrates, such as disease fromfungi, molds, bacteria spores and viruses. These spreadable skindiseases include athletes foot fungus and hairy hoof wart disease, andthe many organisms leading to Mastitis and other mammalian milkingdiseases. The disease can be a viral disease such as parvovirus,coxsackie virus, or herpes virus. The disease can also be bacterial,such as S. aureus, E. coli, Streptococci, etc., or a Mycobacterium typesuch as that leading to tuberculosis. The compositions may also be usedto treat animal carcasses to reduce both pathogenic and non-pathogenicmicrobial levels.

[0055] The antimicrobial compositions can also be used on foods andplant species to reduce surface microbial populations; used atmanufacturing or processing sites handling such foods and plant species;or used to treat process waters around such sites. For example, thecompositions can be used on food transport lines (e.g., as belt sprays);boot and hand-wash dip-pans; food storage facilities; anti-spoilage aircirculation systems; refrigeration and cooler equipment; beveragechillers and warmers, blanchers, cutting boards, third sink areas, andmeat chillers or scalding devices. The compositions of the invention canbe used to treat produce transport waters such as those found in flumes,pipe transports, cutters, slicers, blanchers, retort systems, washers,and the like.

[0056] The antimicrobial compositions have particular value for use onfood packaging materials and equipment, and especially for cold or hotaseptic packaging. The compositions can also be used on or in ware washmachines, dishware, bottle washers, bottle chillers, warmers, third sinkwashers, cutting areas (e.g., water knives, slicers, cutters and saws)and egg washers. Particular foodstuffs that can be treated withcompositions of the invention include eggs; meats, seeds, leaves, fruitsand vegetables. Particular plant surfaces include both harvested andgrowing leaves, roots, seeds, skins or shells, stems, stalks, tubers,corms, fruit, and the like. Particular treatable surfaces includepackaging such as cartons, bottles, films and resins; dish ware such asglasses, plates, utensils, pots and pans; ware wash machines; exposedfood preparation area surfaces such as sinks, counters, tables, floorsand walls; processing equipment such as tanks, vats, lines, pumps andhoses (e.g., dairy processing equipment for processing milk, cheese, icecream and other dairy products); and transportation vehicles.

[0057] The antimicrobial compositions can also be used on or in otherindustrial equipment and in other industrial process streams such asheaters, cooling towers, boilers, retort waters, rinse waters, asepticpackaging wash waters, and the like. The compositions can be used totreat microbes and odors in recreational waters such as in pools, spas,recreational flumes and water slides, fountains, and the like.

[0058] The antimicrobial compositions can also be used to reducemicrobial and viral counts in air and liquids by incorporation intofiltering media or breathing filters, e.g., to remove water and air-bornpathogens such as Legionella.

[0059] Other hard surface cleaning applications for the antimicrobialcompositions of the invention include clean-in-place systems (CIP),clean-out-of-place systems (COP), washer-decontaminators, sterilizers,textile laundry machines, ultra and nano-filtration systems and indoorair filters. COP systems can include readily accessible systemsincluding wash tanks, soaking vessels, mop buckets, holding tanks, scrubsinks, vehicle parts washers, non-continuous batch washers and systems,and the like. CIP systems include a variety of devices that will befamiliar to those skilled in the art, and will typically employ flowrates on the order of about 40 to about 600 liters per minute,temperatures from ambient up to about 70° C., and contact times of atleast about 10 seconds, more preferably about 30 to about 120 seconds.

[0060] The antimicrobial compositions can be applied to microbes or tosoiled or cleaned surfaces using a variety of methods. For example, theantimicrobial composition can be sprayed or wiped onto a surface; thecomposition can be caused to flow over the surface, or the surface canbe dipped into the composition. The compositions can be formulated asliquids, gels, aerosols, waxes, solids, or powders. If steam or anothergaseous diluting solvent is employed, then the compositions can beformulated to be applied in a gaseous state.

[0061] The invention is further illustrated in the followingnon-limiting examples, in which all parts and percentages are by weightunless otherwise indicated. In the examples the following procedureswere employed:

EXAMPLE 1

[0062] Several compositions were evaluated by comparing them against acommercially available aseptic bottle washing biocide based on mixedperacids (MATRIXX™; Ecolab). Compositions containing only 1000 ppm or2000 ppm of a single peracid or mixed peracids were used as controls.The remaining compositions were prepared by adding 10% of varioussolvents to an aqueous solution containing 1000 ppm or 2000 ppm of themixed peracids. Non-solubilizing amounts of anionic surfactants wereadded to some of the compositions to affect minimal coupling and toyield, in some cases, pseudo-stable behavior and at least a partialphase-splitting condition. Addition of such non-stabilizing amountstended to provide partial coupling and improved antimicrobial solutionstability but not necessarily improved microbial control.

[0063] The compositions and controls were evaluated for antimicrobialactivity using the procedure set out in set out in Germicidal andDetergent Sanitizing Action of Disinfectants, Official Methods ofAnalysis of the Association of Official Analytical Chemists, paragraph960.09 and applicable sections, 15th Edition, 1990 (EPA Guideline 91-2),using a 10 second contact time at 60° C. against the mold Chaetomiumfunicola (C. funicola). This brief contact time presented an especiallychallenging test, as evidenced by low observed log order reductionvalues for the controls.

[0064] Set out below in Table I are the run number, solvent, solventdescription (in terms of its water solubility), peracid concentration,anionic surfactant concentration, appearance of the mixtures, after theyhad been allowed to stand for one minute, and observed log orderreduction for C. funicola. The solvent description classified thesolvents as highly soluble (>60% solubility in water), partially soluble(˜20-60%), or sparingly soluble (<20%). TABLE I Anionic Run SolventPeracid Surfactant C. funicola No. Solvent Description ConcentrationConcentration Appearance Log Reduction I-1 None None 2000 ppm¹ 0.0%clear 0.1 I-2 None None 1000 ppm² 0.26% clear 0.05 I-3 None None 2000ppm² 0.52% clear 0.1 I-4 Glycolic acid highly soluble 2000 ppm² 0.62%clear 0.2 I-5 Dimethyl sulfoxide highly soluble 2000 ppm² 0.62% clear0.3 I-6 Hydrocarbon diol³ partially soluble 2000 ppm² 0.62% slightlycloudy 0.4 I-7 Propylene carbonate partially soluble 2000 ppm² 0.62%slightly cloudy 1.6 I-8 Diester blend⁴ sparingly soluble 2000 ppm² 0.62%very cloudy 6.0 I-9 Diester blend⁴ sparingly soluble 2000 ppm¹ 0.0% verycloudy >4.4 I-10 Benzyl alcohol sparingly soluble 2000 ppm² 0.62% verycloudy 5.0 I-11 Benzyl alcohol sparingly soluble 2000 ppm¹ 0.0% verycloudy >4.7

[0065] The compositions containing partially soluble solvents (Run Nos.1-6 and 1-7) exhibited some phase-splitting behavior. The compositionscontaining sparingly soluble solvents (Run Nos. 1-8 through 1-11)exhibited substantial phase-splitting behavior. The results in Table Idemonstrate that the addition of partially soluble and sparingly solublesolvents provided a substantial improvement in the antimicrobialefficacy of a commercial aseptic wash product, as can be seen bycomparing control Run Nos. 1-1 through 1-3 to Run Nos. 1-6 through 1-11.The improved performance of Run Nos. 1-8 through 1-11 was especiallydramatic, in that the observed activity improvement was 5 or more ordersof magnitude compared to control Run Nos. 1-1 through 1-3. Use of highlysoluble solvents (Run Nos. 1-4 and 1-5) provided only a smallimprovement in antimicrobial efficacy.

EXAMPLE 2

[0066] Several antimicrobial compositions of the present invention wereevaluated for biocidal control, using the method of Example 1, andcompared to several commercial products and to formulations from severalU.S. patents. The comparison compositions formed clear (single-phase)formulations when prepared according to instructions. The compositionsof the invention formed pseudo-stable cloudy compositions that underwentphase splitting following application. All tested compositions wereevaluated against the spore-forming, enterotoxin producing pathogensBacillus cereus and Bacillus subtilis and the mold C. funicola using a10 second contact time at 60° C. Set out below in Table II are the runnumber, benzyl alcohol amount, amounts of additional ingredients,appearance of the mixtures, after they had been allowed to stand for oneminute, and observed log order reduction for B. cereus, Bacillussubtilis and C. funicola for each composition. TABLE II Run BenzylAlcohol B. cereus B. subtilis C. funicola No. Amount AdditionalIngredient Amounts¹ Appearance Log Reduction Log Reduction Log Reduction2-1  5.0% DBS² (0.1%) clear (1-phase) 0.2 0.0 >4.4 2-2  2.0% DBS² (0.1%)clear (1-phase) 0.1 — >4.4 2-3  2.0% DBS² (5.0%) clear (1-phase) 0.0 0.20.3 2-4  2.0% Nonionic surfactant³ (5.0%) clear (1-phase) 0.0 0.1 0.42-5  0.0% BUTYL CELLOSOLVE ™ (10.0%), DBS² (2.4%), clear (1-phase) 0.00.2 3.2 anhydrous sodium merasilicate (2.0%)⁴ 2-6  6.0% DBS² (1.3%),ammonium hydroxide 28% (0.2%), clear (1-phase) 0.0 0.1 >4.8Na-octane-1-sulfonate 40% (1.0%),⁵ 2-7  4.0% Ethanol (10%)⁶ clear(1-phase) 0.05 0.1 4.6 2-8  2.0% Ethanol (10%)⁷ clear (1-phase) 0.1 —4.7 2-9  4.0% Glycerine (10%), DBS (2%) + other chemicals⁸ clear(1-phase) 0.1 0.0 4.7 2-10 4.0% Peracid⁹ (0.1%), NAS¹⁰ (0.24%) cloudy(2-phase) >6.3 — >4.4 2-11 3.5% Peracid¹¹ (0.15%) cloudy (2-phase) >6.3— >4.5 2-12 3.0% Peracid¹² (0.1%), NAS¹⁰ (0.24%) cloudy(2-phase) >6.3 >6.7 3.8 2-13 3.0% Peracid⁹ (0.1%, NAS¹⁰ (0.24%) cloudy(2-phase) >6.5 >6.7 4.0 2-14 3.0% Peracid¹³ (0.1%) cloudy (2-phase) >6.2— 3.4 2-15 0.0% Diester blend¹⁴ (5%) peracid¹¹ (0.1%), LAS (0.1%) cloudy(2-phase) 5.0 — >4.4 2-16 0.0% Diester blend¹⁴ (5%), H₂O₂ (2.1%)¹⁵cloudy (2-phase) — 2.9 >4.4 2-17 0.0% Diester blend¹⁴ (5%), H₂O₂(2.1%)¹⁵ cloudy (2-phase) — >6.0 >4.4 2-18 0.0% Diester blend¹⁴ (5%),NaOCl (0.02%)¹⁶ cloudy (2-phase) 6.0 >6.1 >4.8 2-19 5.0% NaOCl (0.02%)¹⁶cloudy (2-phase) — — >4.8 2-20 0.0% Diester blend¹⁴ (2.5%), NaOCl(0.025%)¹⁷ clear (1-phase) >6.0 >6.1 >3.4

[0067] Except as otherwise noted, the comparative compositions in RunNos. 2-1 through 2-9 were prepared according to the listed examples ofthe cited patents or according to the mixing instructions of the citedcommercial products. Each was found to yield a non-phase-splittingformulation. The compositions of the present invention in Run Nos. 2-10through 2-19 yielded phase-splitting formulations that formed at least 2phases. Run No. 2-20 yielded a pseudo-stable solution that was justslightly opaque but did not separate during the test time. Thecompositions of the invention exhibited significant antimicrobialefficacy against B. cereus, as well as broad-spectrum efficacy againstB. subtilis and C. funicola. However, the composition of Run No. 2-19underwent a chemical reaction and could not be employed at the desiredactive level against the Bacillus spores.

EXAMPLE 3

[0068] Using the method of Example 1, 5% portions of various sparinglysoluble solvents were added to plain water or to commercial peracidbottle washing formulas (KX-6091, 15C, or VORTEXX™; Ecolab) and testedagainst the mold C. funicola using a 10 second contact time at 60° C. Anon-emulsifying amount of the anionic surfactant sodium octene sulfonatewas added to some of the compositions to slow down, but not prevent,phase-splitting. Set out below in Table III are the run number, solvent,peracid, peracid concentration, surfactant concentration, appearance ofthe mixtures after they had been allowed to stand for 1 minute, andobserved log order reduction for C. funicola for each composition. TABLEIII Run Peracid Surfactant C. funicola No. Solvent Peracid ConcentrationConcentration Appearance Log Reduction 3-1  None KX-6091¹ 2000 ppm   0ppm clear (1-phase) 0.2 3-2  None 15C¹ 2000 ppm 2500 ppm clear (1-phase)0.2 3-3  None VORTEXX¹ 2000 ppm 5960 ppm clear (1-phase) 0.1 3-4  Glycolsolvents² KX-6091¹ 2000 ppm   0 ppm cloudy (2-phase) 1.3 3-5  Glycolsolvents³ KX-6091¹ 2000 ppm   0 ppm cloudy (2-phase) 3.7 3-6  Glycolsolvents⁴ KX-6091¹ 2000 ppm   0 ppm cloudy (2-phase) 3.2 3-7  Diesterblend⁵ KX-6091¹ 2000 ppm  1000 ppm⁷ cloudy (2-phase) >4.4 3-8  Glycolsolvents⁶ None   0 ppm  1000 ppm⁷ cloudy (2-phase) 2.8 3-9  Glycolsolvents⁶ KX-6091¹ 1000 ppm  1000 ppm⁷ cloudy (2-phase) 4.3 3-10 Glycolsolvents⁶ KX-6091¹ 2000 ppm  1000 ppm⁷ cloudy (2-phase) >4.4 3-112-ethyl-l-hexanol KX-6091¹ 2000 ppm  1000 ppm⁷ cloudy (2-phase) >4.23-12 Dipentene KX-6091¹ 2000 ppm  1000 ppm⁷ cloudy (2-phase) 2.7 3-13Amyl acetate KX-6091¹ 2000 ppm  1000 ppm⁷ cloudy (2-phase) 3.3 3-14Benzyl alcohol None   0 ppm   0 ppm cloudy (2-phase) >4.2 3-15 Benzylalcohol KX-6091¹ 2000 ppm   0 ppm cloudy (2-phase) >4.2 3-16 Tetrabutylammonium hydroxide⁷ 15C¹ 2000 ppm 2500 ppm cloudy (2-phase) 1.7 3-17Phenoxyethanol 15C¹ 2000 ppm 2500 ppm cloudy (2-phase) 3.9 3-18Phenoxyethanol VORTEXX¹ 2000 ppm 5960 ppm cloudy (2-phase) 4.8

[0069] The compositions in Run Nos. 3-3 to 3-18 exhibitedphase-splitting. The results in Table III demonstrate that substantialimprovements in antimicrobial efficacy could be obtained by modifyingall three commercial aseptic wash products, as can be seen by comparingcontrol Run No. 3-1 with Run Nos. 3-4 through 3-7, 3-9 through 3-13 and3-15; control Run No. 3-2 with Run Nos. 3-16 and 3-17; and control RunNo. 3-3 with Run No. 3-18. Run Nos. 3-8 and 3-14 exhibited significantantimicrobial efficacy without an additional antimicrobial agent. Acomposition containing both a sparingly soluble antimicrobially-activesolvent and an additional antimicrobial agent exhibited a synergisticimprovement in performance compared to the use of either theantimicrobially-active solvent or the additional antimicrobial agentalone, as can be seen by comparing Run No. 3-10 with Run Nos. 3-1 and3-8.

EXAMPLE 4

[0070] Using the method of Example 2, varying amounts of severalsparingly soluble solvents were added to commercial peracid bottlewashing formulations (TSUNAMI-100™, MATRIXX™, or KX-6091; Ecolab) andtested against the mold C. funicola using a 10 second contact time at60° C. The surfactant dodecylbenzene sulfonate (“DBS”) was added to someof the compositions to slow down, but not inhibit, phase-splitting. Setout below in Table IV are the run number, solvent, solventconcentration, peracid concentration, DBS concentration, appearance ofthe mixtures after they had been allowed to stand for 1 minute, andobserved log order reduction for C. funicola for each composition. TABLEIV Solvent C. funicola Log Run No. Solvent (%) Peracid (ppm) DBS (ppm)Appearance Reduction 4-1 Benzyl alcohol 10% 2000¹ 1000 cloudy(2-phase) >4.4 4-2 Benzyl alcohol 10% 2000¹ 0 cloudy (2-phase) 3.9 4-3Benzyl alcohol 5% 2000¹ 500 cloudy (2-phase) 4.1 4-4 Benzyl alcohol 1%2000¹ 100 clear (1-phase) 0.1 4-5 None 0% 2000¹ 0 clear (1-phase) 0.14-6 Diester blend⁴ 10% 2000² 1000 cloudy (2-phase) >4.4 4-7 Diesterblend⁴ 10% 2000² 0 cloudy (2-phase) >4.4 4-8 Diester blend⁴ 5% 2000² 500cloudy (2-phase) 4.2 4-9 Diester blend⁴ 2.5% 1500² 0 hazy (2-phase) >4.44-10 Diester blend⁴ 2.5% 1200² 0 hazy (2-phase) >4.4 4-11 Diester blend⁴1% 2000² 100 hazy (2-phase) 1.2 4-12 None 0% 2000² 0 clear (1-phase) 0.24-13 Diester blend² 5% 1000³ 1000 cloudy (2-phase) >4.4 4-14 Diesterblend² 4% 1000³ 0 cloudy (2-phase) >4.4 4-15 Diester blend² 3% 1000³ 0cloudy (2-phase) 3.2 4-16 Diester blend² 2% 1000³ 0 hazy (2-phase) 3.14-17 Diester blend² 2.5% 1500⁷ 0 hazy (2-phase) >4.4 4-18 None 0% 1000³0 clear (1-phase) 0.05 4-19 Solvent Mixture⁵ 5% 2000¹ 0 cloudy (2-phase)3.6 4-20 Solvent Mixture⁵ 1% 2000¹ 0 clear (1-phase) 0.6 4-21Phenoxyethanol 5.0% 2000³ 0 cloudy (2-phase) 4.8 4-22 Phenoxyethanol5.0% 2000⁶ 0 cloudy (2-phase) 3.9 4-23 Phenoxyethanol 2.5% 1200⁶ 0 hazy(2-phase) 3.0 4-24 Phenoxyethanol 2.5% 1500⁶ 0 hazy (2-phase) >4.0 4-25Phenylethanol 3.0% 2000⁶ 0 cloudy (2-phase) >4.5 4-26 Tetrabutylammonium hydroxide, pH = 3.7 5.0% 2000⁶ 0 cloudy (2-phase) >4.5

[0071] For each of the antimicrobial compositions in Table IV,significant antimicrobial efficacy was obtained near, or just above, thesolubility limit of the antimicrobially-active solvent in the dilutingsolvent. The results in Table IV show that substantial improvements inantimicrobial efficacy were obtained by modifying the commercial asepticwash products, as can be seen by comparing control Run No. 4-5 with RunNos. 4-1 through 4-3 and 4-19; control Run No. 4-12 with Run Nos. 4-6through 4-11 and 4-22; and control Run No. 4-18 with Run Nos. 4-13through 4-17. Compositions with and without added surfactant (DBS)exhibited increased antimicrobial activity, as can be seen, for example,from Run Nos. 4-1 through 4-3 and 4-6 through 4-11. Compositionscontaining mixtures of antimicrobially-active solvents are shown in RunNos. 4-19 and 4-20.

EXAMPLE 5

[0072] Using the method of Example 2, varying amounts of benzyl alcoholwere added to commercial peracid bottle washing formulations (KX-6091,15C, TSUNAMI-100™, and VORTEXX™; Ecolab) and tested against thespore-forming, enterotoxin producing pathogen Bacillus cereus and themold C. funicola using a 10 second contact time at 60° C. Set out belowin Table V are the run number, solvent, solvent concentration, peracidconcentration, appearance of the mixtures after they had been allowed tostand for 1 minute, and the observed log order reduction for Bacilluscereus and C. funicola for each composition. TABLE V Run Solvent LogReduction No. Solvent (%) Peracid¹ (ppm) Appearance B. Cereus C.funicola 5-1  None 0% 1000¹ clear 1.2 0.1 5-2  None 0% 2000¹ clear 6.20.2 5-3  None 0% 2000² clear — 0.1 5-4  None 0% 2000³ clear 0.2 0.2 5-5 None 0% 2000⁴ clear 0.1 0.1 5-6  Benzyl alcohol 10% 0 very cloudy⁵— >4.4 5-7  Benzyl alcohol 10% 1000¹ very cloudy⁵ — >4.4 5-8  Benzylalcohol 4.5% 0 very cloudy⁵ 0.1 >4.4 5-9  Benzyl alcohol 4.5% 1000¹ verycloudy⁵ 6.3 >4.4 5-10 Benzyl alcohol 4.0% 0 very cloudy⁶ — >4.4 5-11Benzyl alcohol 4.0% 1000¹ very cloudy⁶ 3.6 >4.4 5-12 Benzyl alcohol 4.0%1000³ very cloudy⁶ 4.8 >4.4 5-13 Benzyl alcohol 3.5% 0 opaque⁶ — 4.25-14 Benzyl alcohol 3.5% 1000¹ opaque⁶ 1.8 >4.4 5-15 Benzyl alcohol 3.5%1000² + 1500² clear >6.3 >4.4> 5-16 Benzyl alcohol 3.5% 2000² clear >6.34.5 5-17 Benzyl alcohol 3.5% 1500³ clear >6.3 >4.5 5-18 Benzyl alcohol3.5% 0 cloudy⁵ 3.4 2.6 5-19 Benzyl alcohol 3.0% 1000¹ clear — 2.7 5-20Benzyl alcohol 3.0% 1000² clear >6.5 3.8 5-21 Benzyl alcohol 3.0% 2000²clear >6.3 >4.7 5-22 Benzyl alcohol 3.0% 2500² clear >6.3 >4.5 5-23Benzyl alcohol 3.0% 1500² clear >6.3 >4.5 5-24 Benzyl alcohol 3.0% 1000³clear >6.5 4.3 5-25 Benzyl alcohol 3.0% 1000⁴ cloudy⁵ >6.5 4.0 5-26Benzyl alcohol 3.0% 1000¹ hazy >6.2 4.0 5-27 Benzyl alcohol 2.5% 1000³clear 6.4 4.2 5-28 Benzyl alcohol 2.5% 1000¹ cloudy⁵ 3.0 4.0 5-29 Benzylalcohol 2.0% 1000³ clear 4.3 2.3 5-30 Benzyl alcohol 2.0% 1000² cloudy⁵4.7 4.0 5-31 Benzyl alcohol 2.0% 1000¹ clear 3.7 3.8 5-32 Benzyl alcohol1.5% 1000³ clear 5.9 1.2 5-33 Benzyl alcohol 1.5% 0 cloudy⁵ 0.05 0.2

[0073] The results in Table V show substantial enhancement inantimicrobial efficacy for compositions both above and below the watersolubility limit (as evidenced visually by solution clarity) of theantimicrobially-active solvent in the diluting solvent. Significantantimicrobial efficacy was also obtained against both organisms usingsome clear solutions (see, e.g., Run Nos. 5-15 through 5-17, 5-20through 5-24, 5-27, 5-29, 5-31 and 5-32).

EXAMPLE 6

[0074] Aqueous mixtures containing 3% or 1% benzyl alcohol solvent and2000 ppm or 1000 ppm of a commercial peracid bottle washing formulation(KX-6091 or VORTEXX™; Ecolab) were prepared. A surfactant was added tosome of the mixtures. The mixtures were tested against the mold C.funicola using a 10 second contact time at 60° C. Set out below in TableVI are the run number, solvent concentration, peracid, surfactant,appearance of the mixtures after they had been all owed to stand for 1minute , and the observed log order reduction for C. funicola for eachcomposition. TABLE VI C. funicola Run Solvent, Peracid Log No. % (ppm)Surfactant Appearance Reduction 6-1 (3%) 2000 ppm¹ None cloudy, phaseseparating 3.4 6-2 (3%) 2000 ppm¹ mixed² clear, 1-phase 0.2microemulsion 6-3 (1%) 1000 ppm³ None clear, 1-phase 0.2 6-4 (1%) 1000ppm  LAS-MIPA⁴ cloudy, phase separating 2.8

[0075] The results in Table VI show that completely emulsifying thesolvent system into a single phase using a surfactant can reduceantimicrobial efficacy, as can be seen by comparing Run Nos. 6-1 and6-2. Conversely, use of a surfactant that can partially solubilize (oreven destabilize) the composition can improve antimicrobial efficacy, ascan be seen by comparing Run Nos. 6-3 and 6-4.

EXAMPLE 7

[0076] Using the method of Example 2, varying amounts of sparinglysoluble solvent blends were added to a peracid bottle washingformulation (15C; Ecolab) and tested against spores of Bacillus subtilisand the mold C. funicola using a 10 second contact time at 60° C. Setout below in Table VII are the run number, solvents, solventconcentrations, peracid concentration, appearance of the mixtures afterthey had been allowed to stand for 1 minute, and the observed log orderreduction for Bacillus cereus and C. funicola for each composition.TABLE VII Run Solvent Peracid² Log Reduction No. Solvent(s) (%) (ppm)Appearance B. subtilis C. funicola 7-1 Diester blend² 2.5% 1500hazy >6.5 >4.4 7-2 Benzyl alcohol 3.5% 1000 hazy 6.1 5.2 7-3 Diesterblend²/benzyl 1.5/1.0% 0 clear 0 >4.4 alcohol 7-4 Diester blend²/benzyl1.0/1.5% 0 clear 0 >4.4 alcohol 7-5 Diester blend²/benzyl 1.0/1.5% 1500clear >6.0 >4.4 alcohol 7-6 Diester blend²/benzyl 1.5/1.0% 1500clear >6.0 >4.4 alcohol

[0077] The results in Table VII show substantial enhancement inantimicrobial efficacy for compositions both above and below the watersolubility limit (as evidenced visually by solution clarity) of theantimicrobially-active solvent. Most notable are the blended solventsystems shown in Run Nos. 7-5 and 7-6, which utilized each solvent belowits solubility limit and a peracid, and provided significantbroad-spectrum antimicrobial efficacy using clear solutions.

EXAMPLE 8

[0078] Using the method of Example 2, a sparingly soluble solvent wasadded to various additional antimicrobial agents and tested againstBacillus cereus, Bacillus subtilis, C. funicola and N. fisheri using a10 second contact time at 60° C. Set out below in Table VIII are the runnumber, solvent and antimicrobial agent employed, solvent amount,antimicrobial agent amount, and the observed log order reduction forBacillus cereus, Bacillus cereus, C. funicola, or N. fisheri for eachcomposition. TABLE VIII Run Solvent + Additional Solvent Additional LogReduction No. Antimicrobial Agent(s) Amount Agent Amount B. cereus B.subtilis C. funicola N. fisheri 8-1 Diester blend¹ + NaOCl⁵ 2.5% 200ppm >6.3 >6.0 >4.4 >4.6 8-2 Diester blend¹ + NaOCl⁵ 2.5% 400 ppm— >6.0 >4.4 — 8-3² Diester blend¹ + H₂O₂ 5.0% 2.1% —  2.9 >4.4  2.1 8-4²Diester blend¹ + H₂O₂ 5.0% .2% — >6.0 >4.4 — 8-5 Diester blend¹ + 2.5%800 + 1500 ppm — — >4.8 — C₈FA³ + POAA⁴ 8-6 Diester blend¹ 1.5% 0 — —0.2 — 8-7 C₈FA³ 800 ppm 0 — — 0.2 — 8-8 POAA⁴ 1500 ppm 0 — — 0.2 —

[0079] The results in Table VIII illustrate use of various combinationsof solvents and additional antimicrobial agents in the presentinvention. The mixture shown in Run No. 8-5 gave an especiallysynergistic result compared to the three control compositions of RunNos. 8-6 through 8-8.

EXAMPLE 9

[0080] Using the method of Example 2, a composition was tested againstthe spore Bacillus cereus and the mold C. funicola using a 120 secondcontact time at 40° C. These experiments were run in order to determinethe antimicrobial effectiveness of a composition of the presentinvention at a lower treatment temperature. Set out below in Table IXare the run number, solvent and additional antimicrobial agent, solventamount, additional antimicrobial agent amount, and the observed logorder reduction for Bacillus cereus and C. funicola for eachcomposition. TABLE IX Run Solvent + Additional Solvent Log Reduction No.Antimicrobial Agent (%) Additional Agent Amount B. cereus C. funicola9-1  Diester blend¹ + NaOCl 2.5%  200 ppm >6.3 3.2 9-2² Diester blend¹ +H₂O₂ 3.0% 0.84% >6.3 1.0 9-3² Diester blend¹ + H₂O₂ 2.5%  .70% >6.3 1.09-4  Diester blend¹ + POAA³ 2.5% 1500 ppm >6.3 2.7

[0081] The results in Table IX demonstrate the ability to induceeffective microbial control at lower treatment temperatures.

EXAMPLE 10

[0082] Aqueous mixtures containing an antimicrobially-active solvent, aperacid, or mixtures of both were prepared and evaluated against thespore-forming, enterotoxin producing pathogen Bacillus cereus using a 10second contact time at 60° C. Set out below in Table X are the runnumber, solvent, solvent concentration, peracid concentration, and theobserved log order reduction for B. cereus for each composition. TABLE XRun Solvent, Peracid B. cereus Lo2 No. Solvent (wt %) (ppm) Reduction10-1 None   0% 1000¹ 0.2 10-2 None   0% 3000¹ 0.9 10-3 None   0% 4000²0.8 10-4 Benzyl alcohol   3% 0 0.1 10-5 Benzyl alcohol   3% 1000¹ 2.410-6 Diester blend³   3% 0 0.3 10-7 Diester blend³   3% 1000² 3.6 10-8Diester blend³ 2.5% 1500⁴ >6.3

[0083] The results in Table X show the substantial synergisticimprovements in sporicidal efficacy that tan be obtained by combiningthe antimicrobially-active solvent and a peracid, as can be seen bycomparing Run Nos. 10-1, 10-4 and 10-5, and Run Nos. 10-3, 10-6 and10-7. Run No. 10-7 provided nearly a 3-log reduction improvementcompared to the use of the antimicrobially-active solvent or peracidalone, while using a lower quantity of peracid. Run No. 10-8 provided anespecially effective sporicide at even lower levels ofantimicrobially-active solvent and peracid.

EXAMPLE 11

[0084] Using the method of Example 10, aqueous mixtures containing 3%benzyl alcohol, or varying amounts of several peracids (KX-6091,MATRIXX™, TSUNAMI 100™ or OXONIA ACTIVE™; Ecolab), or mixtures of bothbenzyl alcohol and peracid were prepared and evaluated as possiblesterilant formulations against the spore-forming, enterotoxin producingpathogen Bacillus cereus using a 10 second contact time at 60° C. Setout below in Table VIII are the run number, solvent, peracidconcentration, and the observed log order reduction for B. cereus foreach composition. TABLE XI Peracid, B. cereus Log Run No. SolventSolvent, (wt %) (ppm) Reduction 11-1 Benzyl alcohol 3% 1000¹ >6.5 11-2Benzyl alcohol 3% 1000² >6.5 11-3 Benzyl alcohol 3% 1000³ >5.6 11-4Benzyl alcohol 3% 1000⁴ 2.4 11-5 Benzyl alcohol 3% 1000⁵ >6.3 11-5Benzyl alcohol 3% None 0.1 11-6 None 0% 4000⁴ 0.8 11-7 None 0% 4000² 0.8

[0085] The results in Table XI show the substantial synergisticimprovements in sporicidal efficacy that can be obtained by combiningthe antimicrobially-active solvent and a peracid. For example, Run No.11-2 provided more than a 6-log reduction improvement compared to theuse of the antimicrobially-active solvent alone (Run No. 11-5), andnearly a 6-log reduction improvement compared to the use of the peracidalone (Run No. 11-7), yet required only one-fourth as much peracid.

EXAMPLE 12

[0086] Using the method of Example 10, aqueous mixtures containingvarious solvents and varying amounts of a peracid (15C; Ecolab) wereprepared and evaluated against the spore-forming, enterotoxin producingpathogen Bacillus cereus using a 10 second contact time at 60° C. Setout below in Table XII are the run number, solvent type andconcentration, peracid type and concentration, and the observed logorder reduction for B. cereus for each composition. As shown, a widerange of chemical solvent classes yielded substantial spore reductions.TABLE XII Run Solvent Type and Amount Peracid Type and - B. cereus LogNo. (wt %) Amount (ppm) Reduction 12-1 Phenoxyethanol (2.5%) 15C¹ (1200ppm) 3.4 12-2 Phenethanol (3.0%) 15C¹ (2000 ppm) >6.4 12-3 Benzoic acid(0.5%) 15C¹ (2000 ppm) >6.0 12-4 Benzyl benzoate (0.5%) 15C¹ (2000 ppm)2.3 12-5 Diester blend² (2.5%) 15C¹ (1200 ppm) >6.2

EXAMPLE 13

[0087] Using the method of Example 10, aqueous mixtures containingvarying types and amounts of solvents and varying types and amounts ofseveral peracids were prepared and evaluated as sporicides againstBacillus subtilis, using a 10 second contact time at 60° C. Set outbelow in Table XIII are the run number, solvent, solvent concentration,peracid type and concentration, and the observed log order reduction forB. subtilis for each composition. TABLE XIII Peracid B. subtilis RunSolvent Type and Amount, Log No. Solvent wt % ppm Reduction 13-1 Benzylalcohol 3.0% VORTEXX ™^(.1) >6.7 (1000 ppm) 13-2 Benzyl alcohol 3.0%VORTEXX ™^(.1) >6.7 (1500 ppm) 13-3 Benzyl alcohol 3.5%VORTEXX ™^(.1) >6.7 (1000 ppm) 13-4 Benzyl alcohol 3.0%VORTEXX ™^(.1) >6.7 (1500 ppm) 13-5 Benzyl alcohol 3.5% 15C² (1000 ppm)5.6 13-6 Benzyl alcohol 2.5% VORTEXX ™^(.1) >6.7 (1500 ppm) 13-7 Benzylalcohol 2.0% VORTEXX ™^(.1) >6.7 (1500 ppm) 13-8⁴ Benzyl alcohol 2.0%TSUNAMI 100 ™^(.3) >6.7 (1000 ppm) 13-9 Phenoxyethanol 5.0% 15C² (1000ppm) 6.7 13-10 Phenoxyethanol 5.0% VORTEXX ™^(.1) 6.7 (1000 ppm) 13-11Phenoxyerhanol 2.5% 15C² (1500 ppm) >6.5 13-12 Phenoxyethanol-tetra 5.0%15C² (1000 ppm) 6.7 ethoxylate 13-13 Diester blend⁵ 2.5% 15C² (1500ppm) >6.5 13-14 Diester blend⁵ 1.5% VORTEXX ™^(.1) >6.7 (1500 ppm) 13-15Tert-butanol 5.0% VORTEXX ™^(.1) >6.7 (1500 ppm)

EXAMPLE 14

[0088] Using the method of Example 2, aqueous mixtures containing 2.5wt.% DBE-3™ solvent (diester blend, DuPont Nylon) and a peracid wereprepared and evaluated as a general antimicrobial agent against S.aureus, E. coli, or N. fisheri using a 10 second contact time at 60° C.Set out below in Table XIV are the run number, peracid type and amount,and the observed log order reduction for each organism. TABLE XIV RunPeracid Type Log Reduction No. and Amount (ppm) S. aureus E. coli N.fisheri 14-1 15C¹ (2000 ppm) — — 3.7 14-2 OXONIA ACTIVE ™^(.2) >7.2 >7.1(75 ppm)

[0089] Various modifications and alterations of this invention will beapparent to those skilled in the art without departing from the scopeand spirit of this invention. It should be understood that thisinvention is not limited to the illustrative embodiments set forthabove.

We claim:
 1. A method for antimicrobial treatment comprising applying tomicrobes a composition containing a diluting solvent, anantimicrobially-active solvent having a density different from thedensity of the diluting solvent, and an optional cosolvent, surfactant,or additional antimicrobial agent, wherein the amount ofantimicrobially-active solvent or additional antimicrobial agent issufficiently high and the amount of cosolvent or surfactant issufficiently low so that the composition will provide greater than a1-log order reduction in the population of spores or bacteria ofBacillus cereus within 10 seconds at 60° C.
 2. A method according toclaim 1 wherein the diluting solvent comprises water.
 3. A methodaccording to claim 1 wherein the composition comprises such additionalantimicrobial agent.
 4. A method according to claim 3 wherein theadditional antimicrobial agent comprises an oxidizing or non-oxidizingcompound selected from the group consisting of hydrogen peroxide,organic peroxides, peracids, carboxylic acids, carboxylic esters, activehalogen compounds, sulfonic acids, iodo-compounds, phenolic derivatives,quaternary ammonium compounds, and mixtures thereof.
 5. A methodaccording to claim 1 wherein the composition will also provide greaterthan a 1-log order reduction in the population of the mold Chaetomiumfunicola within 10 seconds at 60° C.
 6. A method according to claim 1wherein the treatment comprises applying the composition to a hardsurface, soft surface, porous surface, food substance or skin.
 7. Amethod according to claim 1 wherein the treatment comprises applying thecomposition to food packaging and the composition will provide greaterthan a 3-log order reduction in the population of bacteria or spores ofBacillus cereus within 10 seconds at 60° C.
 8. A method according toclaim 7 wherein the food packaging is aseptic food packaging.
 9. Amethod according to claim 1 wherein the treatment comprises applying thecomposition to hospital or surgical linens or garments and wherein thecomposition will provide greater than a 3-log order reduction in thepopulation of bacteria or spores of Bacillus cereus within 10 seconds at60° C.
 10. A method according to claim 1 wherein the treatment comprisessanitizing a solution or hard surface and wherein the composition willprovide greater than a 3-log order reduction within 10 seconds at 60° C.in the population of bacteria or spores of the Bacillus species in suchsolution or on such surface.
 11. A method according to claim 1 whereinthe treatment comprises disinfecting a hard surface and wherein thecomposition will provide greater than a 5-log order reduction within 10seconds at 60° C. in the population of bacteria or spores of theBacillus species on such surface.
 12. A method according to claim 1wherein the treatment acts as a sporicide in a solution or on a hardsurface and wherein the composition will provide greater than a 5-logorder reduction within 10 seconds at 60° C. in the population ofbacteria or spores of the Bacillus species in such solution or on suchsurface.
 13. A method according to claim 1 wherein the treatmentcomprises sterilizing a hard surface and wherein the composition willprovide substantially complete elimination of the population of bacteriaor spores of the Bacillus species on such surface.
 14. A methodaccording to claim 1 wherein the treatment comprises reducing microbialor viral populations on a surface or object or in a body or stream ofwater.
 15. A method according to claim 1 wherein the treatment comprisesa teat dip, hard surface cleaner, sanitizer, disinfectant, sterilizer,surgical garment treatment, ware wash, wash water treatment, bleach,laundry liquid, plant treatment or food treatment.
 16. An antimicrobialconcentrate and instructions for mixing the concentrate with water,wherein the concentrate comprises an antimicrobially-active solvent thathas a density different from that of water, an optional cosolvent orsurfactant, and an optional additional antimicrobial agent, the amountsof antimicrobially-active solvent and optional additional antimicrobialagent being sufficiently high and the amount of cosolvent or surfactantbeing sufficiently low so that when the concentrate is mixed with wateraccording to the instructions the resulting mixture will provide greaterthan a 1-log order reduction in the population of bacteria or spores ofBacillus cereus within 10 seconds at 60° C.
 17. A concentrate accordingto claim 16 wherein the amount of antimicrobially-active solvent issufficiently high and the amount of cosolvent or surfactant issufficiently low so that a clear single-phase solution or microemulsionis not formed when the concentrate is mixed with water according to theinstructions.
 18. A concentrate according to claim 16 comprising saidadditional antimicrobial agent, wherein the amounts ofantimicrobially-active solvent and of additional antimicrobial agent aresufficiently high and the amount of cosolvent or surfactant aresufficiently low so that when the concentrate is mixed with wateraccording to the instructions the resulting mixture will provide greaterthan a 3-log order reduction in the population of spores or bacteria ofBacillus cereus within 10 seconds at 60° C.
 19. A concentrate accordingto claim 18 comprising said additional antimicrobial agent, wherein whenthe concentrate is mixed with water according to the instructions theresulting mixture yields a clear solution.
 20. A concentrate accordingto claim 18 wherein the additional antimicrobial agent comprises anoxidizing or non-oxidizing compound selected from the group consistingof hydrogen peroxide, organic peroxides, peracids, carboxylic acids,carboxylic esters, active halogen compounds, sulfonic acids,iodo-compounds, phenolic derivatives, quaternary ammonium compounds, andmixtures thereof.
 21. A concentrate according to claim 18 wherein theadditional antimicrobial agent comprises a peracid, peroxide, or activehalogen compound.
 22. A concentrate according to claim 21 wherein theadditional antimicrobial agent comprises peroxyacetic acid, hypochlorousacid, hypobromous acid, iodine monochloride, iodine dichloride, iodinedibromide, or chlorine dioxide.
 23. A concentrate according to claim 21wherein the amounts of antimicrobially-active solvent and peracid aresufficiently high and the amount of cosolvent or surfactant aresufficiently low so that when the concentrate is mixed with wateraccording to the instructions the resulting mixture will provide greaterthan a 4-log order reduction in the population of bacteria or spores ofBacillus cereus within 10 seconds at 60° C.
 24. A concentrate accordingto claim 18 wherein the composition will also provide greater than a1-log order reduction in the population of the mold Chaetomium funicolawithin 10 seconds at 60° C.
 25. An antimicrobial composition comprisinga diluting solvent, an antimicrobially-active solvent having a densitythat is different from the density of the diluting solvent, and anoptional cosolvent, surfactant, or additional antimicrobial agent,wherein the amounts of antimicrobially-active solvent and of additionalantimicrobial agent are sufficiently high and the amount of cosolvent orsurfactant are sufficiently low so that the composition will providegreater than a 1-log order reduction in the population of bacteria ofBacillus cereus within 10 seconds at 60° C.
 26. A composition accordingto claim 25 wherein the composition exhibits pseudo-stablephase-splitting behavior.
 27. A composition according to claim 25wherein the composition exhibits quasi-stable behavior.
 28. Acomposition according to claim 25 wherein the composition is not a clearsingle-phase solution or microemulsion.
 29. A composition according toclaim 25 wherein the diluting solvent comprises water.
 30. A compositionaccording to claim 29 wherein the antimicrobially-active solvent isdenser than water.
 31. A composition according to claim 30 wherein afterapplication of the composition to a surface a predominantlyantimicrobially-active solvent layer will form on the surface and apredominantly aqueous layer will form on the antimicrobially-activesolvent layer.
 32. A composition according to claim 25 wherein theantimicrobially-active solvent comprises a polar solvent.
 33. Acomposition according to claim 32 wherein the polar solvent comprises anether, aromatic alcohol, dialkyl diester, or mixtures thereof.
 34. Acomposition according to claim 32 wherein the polar solvent comprises atleast one of benzyl alcohol, ethylene glycol phenyl ether, propyleneglycol phenyl ether, propylene carbonate, phenoxyethanol, dimethylmalonate, dimethyl succinate, diethyl succinate, dibutyl succinate,dimethyl glutarate, diethyl glutarate, dibutyl glutarate, dimethyladipate, diethyl adipate, dibutyl adipate, or mixtures thereof.
 35. Acomposition according to claim 32 wherein the polar solvent comprisesbenzyl alcohol.
 36. A composition according to claim 25 wherein thediluting solvent comprises water and the antimicrobially-active solventhas a water solubility less than about 10% by weight.
 37. A compositionaccording to claim 36 wherein the antimicrobially-active solvent has awater solubility less than about 5% by weight.
 38. A compositionaccording to claim 36 wherein the antimicrobially-active solvent has awater solubility less than about 2% by weight.
 39. A compositionaccording to claim 25 containing water and at least about 10 weight %antimicrobially-active solvent.
 40. A composition according to claim 25containing water and at least about 50 weight % antimicrobially-activesolvent.
 41. A composition according to claim 25 containing water andabout 75 weight % to about 95 weight % antimicrobially-active solvent.42. A composition according to claim 25 wherein theantimicrobially-active solvent comprises benzyl alcohol, ethylene glycolphenyl ether, propylene glycol phenyl ether, propylene carbonate,phenoxyethanol, dimethyl malonate, dimethyl succinate, diethylsuccinate, dibutyl succinate, dimethyl glutarate, diethyl glutarate,dibutyl glutarate, dimethyl adipate, diethyl adipate, dibutyl adipate,or mixtures thereof, and the composition contains no more than about 3weight % surfactant.
 43. A composition according to claim 25 wherein thecomposition comprises said additional antimicrobial agent, and theadditional antimicrobial agent comprises at least one of a carboxylicacid, carboxylic ester, sulfonic acid, active halogen compound, activeoxygen, compound, phenolic derivative or quaternary ammonium compound.44. A composition according to claim 43 wherein the additionalantimicrobial agent comprises a peracid.
 45. A composition according toclaim 44 wherein the peracid comprises peroxyacetic acid.
 46. Acomposition according to claim 43 wherein the amounts ofantimicrobially-active solvent and of additional antimicrobial agent aresufficiently high and the amount of cosolvent or surfactant aresufficiently low so that composition will provide greater than a 2-logorder reduction in the population of bacteria or spores of Bacilluscereus and in the population of the mold Chaetomium funicola within 10seconds at 60° C.
 47. A composition according to claim 43 wherein theamounts of antimicrobially-active solvent and of additionalantimicrobial agent are sufficiently high and the amount of cosolvent orsurfactant are sufficiently low so that composition will provide greaterthan a 4-log order reduction in the population of bacteria or spores ofBacillus cereus and in the population of the mold Chaetomium funicolawithin 10 seconds at 60° C.
 48. A composition according to claim 25wherein the composition comprises a cosolvent comprising at least one ofdiethylene glycol butyl ether or dipropylene glycol butyl ether.
 49. Acomposition according to claim 25 wherein the composition issubstantially surfactant-free.